Research Document - 2010/087

Alternate Ballast Water Exchange Zones for the Newfoundland and Labrador Region – An Aquatic Invasive Species Risk Assessment Based on Oceanographic Modelling, Ecologically and Biologically Significant Areas and the Sustainability of Fisheries and Aquaculture

By C.H. McKenzie, G. Han, M. He, T. Wells, and G. Maillet

Abstract

The scientific advice on alternate ballast water exchange zones (ABWEZ) for the Newfoundland and Labrador region is based on oceanographic modelling (dispersion results), ecologically and biologically significant areas (EBSAs) and the sustainability of fisheries and aquaculture. Potential exchange zones are based on individual vessel routes approaching the Newfoundland and Labrador region and areas of the northwest Atlantic Ocean. The spatial distribution of the surface concentration and the temporal and spatial variation of the dispersion area are all taken into account. EBSAs, identified as part of the Integrated Management strategy for the Placentia Bay - Grand Bank (PBGB) Large Ocean Management Area (LOMA), have also been considered in this risk assessment; as have the areas significant to commercial fisheries and aquaculture. This study presents a first quantitative assessment of ballast water exchange off Newfoundland based on verified model circulation patterns and extensive numerical drift experiments. The potential exchange zones are based on the monthly-mean circulation fields fixed at the 1-m depth. The sensitivity study has indicated some evident impacts of vertical turbulence, while inclusion of the vertical current, weather-band currents and diel migration have limited effects on horizontal dispersion patterns.

Based on the review of the current navigation conditions and the ecological sensitivities of the areas for potential ABWEZs on the east coast of Newfoundland and Labrador, no ABWEZ’s are being recommended at this time. For the northeastern coast of Newfoundland an ABWEZ could be located at least 50 nautical miles offshore and in depths greater than 500 m; but further research is needed before any formal recommendation is made.

The scientific review of marine traffic around Newfoundland and Labrador indicates that domestic and coastal commercial traffic would represent a higher risk of aquatic invasive species invasion than international commercial traffic under the current regulations.

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